Eur. Phys. J. B (2016) 89: 180
https://doi.org/10.1140/epjb/e2016-70302-5

Regular Article

Ferromagnetism of the repulsive atomic Fermi gas: three-body recombination and domain formation

¹ Theoretische Physik, ETH Zurich, 8093 Zurich, Switzerland
² Beijing National Lab for Condensed Matter Physics and Institute of Physics, Chinese Academy of Sciences, Beijing 100190, P.R. China

^a e-mail: wanglei@iphy.ac.cn

Received: 14 May 2016
Received in final form: 25 June 2016
Published online: 8 August 2016

Abstract

The simplest model for itinerant ferromagnetism, the Stoner model, has so far eluded experimental observation in repulsive ultracold fermions due to rapid three-body recombination at large scattering lengths. Here we show that a ferromagnetic phase can be stabilised by imposing a moderate optical lattice. The reduced kinetic energy drop upon formation of a polarized phase in an optical lattice extends the ferromagnetic phase to smaller scattering lengths where three-body recombination is small enough to permit experimental detection of the phase. We also show, using time dependent density functional theory, that in such a setup ferromagnetic domains emerge rapidly from a paramagnetic initial state.